[mapserver-dev] RFC for XMP metadata support

[Paul Ramsey]

Devs,

I've prepared a draft RFC for adding embedded metadata into output
images produced by MapServer.

  http://trac.osgeo.org/mapserver/attachment/ticket/3932/ms-rfc-7X.txt

I'm looking for feedback now before I number and commit it and ask for
a vote. Here's the preamble so you don't have to click:

XMP is the "extensible metadata platform" [1]_ which allows the
embedding of metadata information across a wide range of document and
image formats: PNG, GIF, JPEG, PDF, etc. XMP was originally developed
by Adobe [2]_ and is supported across their product line. It is now
being increasingly included in other standards for metadata embedding
and supported by tools for viewing image information (e.g. exiftools).
Creative Commons has standards for using XMP to embed commons
licensing [3]_ in images and other document, including a specific
creative commons schema. One of the challenges of advertising
licensing and terms of use in WMS and other web mapping services is
that the terms are usually advertised separately from the actual
content. So a WMS service might specify terms in the Capabilities
document, but the images themselves will be unmarked. Embedding
license URLs inside the images themselves using a standard marking
allows organizations to be unambiguous about the conditions attached
to their content.

The goal of this change is to allow users the option of embedding XMP
metadata in their MapServer output using an open source XMP utility
library.

.. [1] http://en.wikipedia.org/wiki/Extensible_Metadata_Platform
.. [2] http://www.adobe.com/products/xmp/overview.html
.. [3] http://wiki.creativecommons.org/XMP
.. [4] http://libopenraw.freedesktop.org/wiki/Exempi

Thanks,
Paul